Body-worn EMF monitor - 29 May 2019 - Accutronics

For those working with high-intensity electromagnetic fields (EMF), such as in the near field region of radar antennas, broadcast transmitters or cellular base stations, it is vital to wear personal safety equipment (PSE) that gives a warning when critical EMF values are reached, to exclude health risks.

Narda Safety Test Solutions has now developed the RadMan 2 for this complex monitoring task, with future 5G applications also in mind. This small device that is worn on the body gives insistent, timely and reliable warning of impermissibly high levels of exposure to electromagnetic radiation.

The shaped frequency response of the personal monitor ensures that the correct alarm threshold is automatically set for the entire frequency range. The permitted limit values specified in the standards are variable, depending on frequency.

As the device has sensors for the E field (electric) as well as for the H field (magnetic), the distance between the field source and the person is immaterial – whether in a strong electric or magnetic field. The higher value of either will always trigger the alarm and will be displayed as a percentage of the applicable upper limit, e.g. as stipulated by ICNIRP. The warning itself cannot be missed, even in harsh, noisy and adverse conditions as it is bright, loud, and the device also vibrates.

Starting and safely using the device is simple. The automatic sensor test checks that the sensors are functioning correctly as soon as the device is switched on, meaning that an external test generator is not needed. A special RF absorber between the sensor and the body ensures that the actual field strength is measured accurately and correctly during operation by eliminating effects of the body such as reflections, which could falsify the results.

It is easy to release the robust, weatherproof device in its IP65 rated housing from its holder with one hand, such as to determine the field exposure isotropically when searching for leaks at cable connectors. This ensures the reliable display of all hotspots in both the E field and the H field, regardless of the orientation of the device. The built-in rechargeable batteries give 800 hours of operating time from a single charge cycle.

The new radiation monitor is available in two versions: the less expensive LT model for up to 8 GHz, with reduced features and fewer functions, and the XT with a range of up to 60 GHz. Exclusive to the XT version is the ‘RF detection’ mode with its tone search function, which allows for a precise isotropic search for leaks at arm’s length. As the field source is approached, the change in the pitch of the tone allows the operative to quickly, simply and reliably check that the antenna is actually switched off before getting too close. Finally, the ‘Pulse’ mode setting causes the alarm to respond much faster, allowing the reliable detection of brief, pulsed signals.

For more information contact Tobie Muller, Accutronics, +27 11 782 8728, tmuller@accutronics.co.za, www.accutronics.co.za